A plasma arc is a gas ionized arc formed between a nonconsumable electrode and a workpiece which is constricted through the discharge outlet of a nozzle in confluence with a stream of gas preferably in the form of a gas vortex. A plasma arc system includes the plasma arc torch and power supply in combination. The volt ampere characteristic of the plasma arc power supply will determine the degree to which current can be held constant through the arc with varying arc length. At a relatively low current output of below 60 amperes and particularly below about 30 amperes it has been difficult to sustain a constant current arc with a torch standoff above 1/16 inch using nitrogen or air as the plasma gas. Torch standoff represents the distance separating the end of the torch and the workpiece. In a conventional plasma arc system, it is difficult to sustain the plasma arc at such low current levels. Moreover at low operating current levels the cutting performance is sensitive to a change in torch standoff. Accordingly, it has been the practice heretofore to operate a plasma arc system for cutting at constant current levels of above 50 amperes.